1// SPDX-License-Identifier: GPL-2.0-or-later
2/*
3 *
4 * Copyright Jonathan Naylor G4KLX (g4klx@g4klx.demon.co.uk)
5 */
6#include <linux/module.h>
7#include <linux/proc_fs.h>
8#include <linux/kernel.h>
9#include <linux/interrupt.h>
10#include <linux/fs.h>
11#include <linux/types.h>
12#include <linux/sysctl.h>
13#include <linux/string.h>
14#include <linux/socket.h>
15#include <linux/errno.h>
16#include <linux/fcntl.h>
17#include <linux/in.h>
18#include <linux/if_ether.h>	/* For the statistics structure. */
19#include <linux/slab.h>
20#include <linux/uaccess.h>
21
22#include <asm/io.h>
23
24#include <linux/inet.h>
25#include <linux/netdevice.h>
26#include <linux/etherdevice.h>
27#include <linux/if_arp.h>
28#include <linux/skbuff.h>
29
30#include <net/ip.h>
31#include <net/arp.h>
32
33#include <net/ax25.h>
34#include <net/netrom.h>
35
36/*
37 *	Only allow IP over NET/ROM frames through if the netrom device is up.
38 */
39
40int nr_rx_ip(struct sk_buff *skb, struct net_device *dev)
41{
42	struct net_device_stats *stats = &dev->stats;
43
44	if (!netif_running(dev)) {
45		stats->rx_dropped++;
46		return 0;
47	}
48
49	stats->rx_packets++;
50	stats->rx_bytes += skb->len;
51
52	skb->protocol = htons(ETH_P_IP);
53
54	/* Spoof incoming device */
55	skb->dev      = dev;
56	skb->mac_header = skb->network_header;
57	skb_reset_network_header(skb);
58	skb->pkt_type = PACKET_HOST;
59
60	netif_rx(skb);
61
62	return 1;
63}
64
65static int nr_header(struct sk_buff *skb, struct net_device *dev,
66		     unsigned short type,
67		     const void *daddr, const void *saddr, unsigned int len)
68{
69	unsigned char *buff = skb_push(skb, NR_NETWORK_LEN + NR_TRANSPORT_LEN);
70
71	memcpy(buff, (saddr != NULL) ? saddr : dev->dev_addr, dev->addr_len);
72	buff[6] &= ~AX25_CBIT;
73	buff[6] &= ~AX25_EBIT;
74	buff[6] |= AX25_SSSID_SPARE;
75	buff    += AX25_ADDR_LEN;
76
77	if (daddr != NULL)
78		memcpy(buff, daddr, dev->addr_len);
79	buff[6] &= ~AX25_CBIT;
80	buff[6] |= AX25_EBIT;
81	buff[6] |= AX25_SSSID_SPARE;
82	buff    += AX25_ADDR_LEN;
83
84	*buff++ = READ_ONCE(sysctl_netrom_network_ttl_initialiser);
85
86	*buff++ = NR_PROTO_IP;
87	*buff++ = NR_PROTO_IP;
88	*buff++ = 0;
89	*buff++ = 0;
90	*buff++ = NR_PROTOEXT;
91
92	if (daddr != NULL)
93		return 37;
94
95	return -37;
96}
97
98static int __must_check nr_set_mac_address(struct net_device *dev, void *addr)
99{
100	struct sockaddr *sa = addr;
101	int err;
102
103	if (!memcmp(dev->dev_addr, sa->sa_data, dev->addr_len))
104		return 0;
105
106	if (dev->flags & IFF_UP) {
107		err = ax25_listen_register((ax25_address *)sa->sa_data, NULL);
108		if (err)
109			return err;
110
111		ax25_listen_release((const ax25_address *)dev->dev_addr, NULL);
112	}
113
114	dev_addr_set(dev, sa->sa_data);
115
116	return 0;
117}
118
119static int nr_open(struct net_device *dev)
120{
121	int err;
122
123	err = ax25_listen_register((const ax25_address *)dev->dev_addr, NULL);
124	if (err)
125		return err;
126
127	netif_start_queue(dev);
128
129	return 0;
130}
131
132static int nr_close(struct net_device *dev)
133{
134	ax25_listen_release((const ax25_address *)dev->dev_addr, NULL);
135	netif_stop_queue(dev);
136	return 0;
137}
138
139static netdev_tx_t nr_xmit(struct sk_buff *skb, struct net_device *dev)
140{
141	struct net_device_stats *stats = &dev->stats;
142	unsigned int len = skb->len;
143
144	if (!nr_route_frame(skb, NULL)) {
145		kfree_skb(skb);
146		stats->tx_errors++;
147		return NETDEV_TX_OK;
148	}
149
150	stats->tx_packets++;
151	stats->tx_bytes += len;
152
153	return NETDEV_TX_OK;
154}
155
156static const struct header_ops nr_header_ops = {
157	.create	= nr_header,
158};
159
160static const struct net_device_ops nr_netdev_ops = {
161	.ndo_open		= nr_open,
162	.ndo_stop		= nr_close,
163	.ndo_start_xmit		= nr_xmit,
164	.ndo_set_mac_address    = nr_set_mac_address,
165};
166
167void nr_setup(struct net_device *dev)
168{
169	dev->mtu		= NR_MAX_PACKET_SIZE;
170	dev->netdev_ops		= &nr_netdev_ops;
171	dev->header_ops		= &nr_header_ops;
172	dev->hard_header_len	= NR_NETWORK_LEN + NR_TRANSPORT_LEN;
173	dev->addr_len		= AX25_ADDR_LEN;
174	dev->type		= ARPHRD_NETROM;
175
176	/* New-style flags. */
177	dev->flags		= IFF_NOARP;
178}
179